The present invention relates to a method for press-molding a frame plate in order to mount a motor for driving a disk, for use as a storage medium, on the frame plate.
A card-type magnetic recording device is inserted into a slot of a portable computer to add to the functions of the portable computer or increase the capacity of processing data.
A casing of the card-type magnetic recording device is stored with various components, such as a disk-type storage medium, motor for rotating the storage medium, recording/reproducing head element for recording information in or reproducing information from the storage medium, mechanism for ejecting a cartridge stored with the disk from the casing, etc.
The casing of the card-type magnetic recording device is composed of an upper cover, a lower cover, and a side frame.
Further, a circuit board for information processing is pasted on the lower surface of the frame, plate.
In general, the external dimensions of the card-type magnetic recording device constructed in this manner are settled according to the PCMCIA (Personal Computer Memory Card International Association) standards. According to Type II of the PCMCIA standards, which is conventionally used very often, the external dimensions of the card-type magnetic recording device (i.e., external dimensions of the casing) are set so that its width, length, and thickness are 54.0 mm, 85.60 mm, and the 5.0 mm, respectively.
Corresponding to this thinness of the casing, the disk drive motor and the recording/reproducing head element are attached individually to recesses that are formed in one frame plate. As the disk drive motor and the recording/reproducing head element are mounted in the frame plate recesses in this manner, they can be fitted better in a space in the casing that is limited in height (thickness) than in the case where the frame plate is mounted on a flat surface, and the attachment is stabilized.
Usually, a recess and a mounting hole for mounting the disk drive motor on the frame plate and a recess and a mounting hole for mounting the recording/reproducing head element are worked by press-molding a material. Normally, however, the material of the frame plate is a steel sheet or stainless-steel sheet. If the material is press-molded to form the mounting recesses and the mounting holes, therefore, pressing force cannot acts equally, owing to the elasticity of the material, and stress strain remains maldistributed on the press-molded frame plate. Practically, therefore, it is hard to obtain the shapes and dimensions of the mounting recesses and the mounting holes that are in conformity to target values.
The object of the present invention is to provide a press molding method capable of accurately forming a recess and a mounting hole for locating a disk drive motor in a frame plate of an information device that stores a disk-shaped storage medium.
In order to achieve the above object, according to the present invention, a frame plate to be mounted with a disk drive motor is obtained by press molding in a manner such that a circular region is set on the frame plate, a motor mounting hole for mounting the disk drive motor is formed in the central portion of the circular region by punching, a recess with a circular cross section is formed by depressing the circular region in the direction of the cross section by backward extrusion molding, and a ring-shaped rising wall is formed around the motor mounting hole, the rising wall projecting in the direction of the cross section.
According to the working method of the present invention, the backward extrusion molding is applied to the formation of the recess for mounting the disk drive motor, so that the influence of deformation on various parts of:the material during the molding process is small, and therefore, high-accuracy press molding can be accomplished. Thus, the motor can be mounted with an appropriate posture in a proper position on the frame plate.
Further, the ring-shaped rising wall is formed around the motor mounting hole that is formed in the center of the base of the recess. By doing this, distortion of the recess, e.g., deformation of the recess that may otherwise be caused when coil relief slots are punched in the base of the recess, can be corrected. In consequence, the base that serves as a reference for the attachment of the disk drive motor is flat, sop that the mounting position for the disk drive motor with respect to the frame plate can be settled accurately.
Thus, the press molding method of the present invention is a suitable press molding method for a frame plate of a thin small-sized device of which the external size is strictly standardized, e.g., a card-type magnetic recording device.